pom.xml: update slf4j to 1.7.22

Changelog: http://slf4j.org/news.html

No functional changes.

Author: php-coder

pom.xml

@@ -441,7 +441,7 @@
 		<skipUnitTests>false</skipUnitTests>
 
 		<!-- Redefine default value from spring-boot-dependencies (https://github.com/spring-projects/spring-boot/blob/v1.4.3.RELEASE/spring-boot-dependencies/pom.xml) -->
-		<slf4j.version>1.7.21</slf4j.version>
+		<slf4j.version>1.7.22</slf4j.version>
 
 		<sortpom.plugin.version>2.5.0</sortpom.plugin.version>